From the back cover:
It’s a lonely life investigating grisly affairs and confronting unnameable horrors, and it requires all sorts of materials that can’t be bought at the corner store as well as information that isn’t found in mass-market publications. Sometimes it seems like an investigator is all on his or her own, with no one to turn to for advice, assistance, or just fairly-priced goods of a specific nature. But if you wander down the right back alley, you may be surprised what you find.
A Peculiar Pentad presents five shops that every investigator may want, or need, to visit - a rare book store where the proprietor quotes from texts that were supposedly lost to the ages; a repair shop whose owner can get any mechanical device, no matter where or when it was made, functioning as good as new - probably better; a private social club that caters to those who have seen things no human ever should, and more.
Written by a quintet of fan-favorite and award-winning game designers including Jeff Grubb, Gwendolyn F.M. Kestrel, Jeff Quick, John D. Rateliff, and Thomas M. Reid, A Peculiar Pentad is the first in a series of sourcebooks designed to provide resources and inspiration to Call of Cthulhu players and Keepers alike.